Yes Christians are to get involved in politics in order to make the country a better place. It is not everybody that calls himself a Christian, is a true Christian because most of them don't practice Christianity. For instance,the catholic church Pope is the head of all christains in the world,if a Christian country is having challenges in good leadership or maltreatment of citizens by the government,the Pope can visit such country to see the president or send representatives to put the president back on track on the right way he is suppose to lead his people.

  God is the best leader,therefore a good Christian that practices his faith will also be a good leader because he will be directed by God. Go back to your bible and see it yourself.